Seismic or elastic wave stimulation is a known technique for enhancing oil recovery from an oil-bearing bed, as described in "Elastic-Wave Stimulation of Oil Production: A Review of Methods and Results," Geophysics Vol. 59, No. 6 (June 1994). One method of generating seismic stimulation is shown in Russian Federation Patent No. 2,001,254, in which two rotating imbalanced weights cause vibration of a platform on the surface. The weight, energy and resonance frequency of the vibration generator are calculated in accordance with the physical and mechanical properties of the ground above the oil bed, and harmonic waves are induced and propagated to the oil bearing level. The main disadvantage of this method is its low efficiency; loss of energy during wave passage from the surface to the oil bed may be as high as 98% and more.
Another known method is shown in Russian Federation Patent No. 1,710,709, in which an anvil plate is dropped to the bottom of the well and a heavy weight (water-filled tubing) is repeatedly lifted and dropped onto the anvil plate, imparting vibrations into the oil bed. Although this method avoids the energy loss associated with vibration generated at the surface, it is inefficient because the force of the falling weight is directed vertically, thus limiting the energy of the elastic vibrations imparted lateral to the well. Additionally, the repeated striking of the well bottom eventually destroys that surface.
The object of the present invention is to increase the effectiveness of the wave generation wells by increasing intensity of the elastic oscillations in the oil-bearing formation and optimization of their number. Another objective of the invention is to reduce additional expenditures for setting and drilling out of cement bridges in wave generation wells and to minimize the cost of installing and maintaining the equipment required for wave stimulation of oil-bearing formations.